Along with proper storage, keeping pump parts clean is critical to maintaining the safety of expressed milk.
When I travel, I carry two sets of cleaning supplies. In my pump bag, I carry a 3-ounce countainer of regular dish soap, a foam cleaning cloth, and a microfiber cloth. My pump bag also came with a plastic placemat that I use as a make-shift drying rack. In my checked bag, I carry a medium-sized container of dish soap, a sponge, and two microfiber cloths (as a drying platform and staging area).
Once, I forgot my dish soap at home (which led to my carrying a back up in my checked bag) and was tempted to use the shower gel or bar soap in my hotel room. Neither of these cleaning agents will work. Instead, find a grocery store or drug store and buy the local dish-washing liquid. Frequently, bathroom soaps and gels have fragrances and lotions that will stay behind on the parts and contaminate the milk.